IMO the most important skill set in self-defense is footwork. Without proper footwork, everything else fails. Think of it as the wheels/axle/drive train of a car. Without those in place, you are going nowhere.
So footwork in combat refers to the way a fighter uses their legs and feet to move during a fight, keeping balance, controlling distance, and creating angles. Good footwork is crucial for offense and defense, allowing fighters to get into advantageous positions and avoid being hit. It involves a combination of balance, groundedness, angles, rhythm, and agility.
Now not all footwork from all fighting arts though translates well to self-defense. You must keep in mind that by its very nature, self-defense is not as “clean” as a ring match. A self-defense situation requires simple footwork that will not compromise your balance. You must account for uneven ground/pavement and environmental conditions.
TIP: Practice simple step advances, retreats and side-steps. Avoid shuffles, slides and cross-steps. Also use every opportunity to practice on different types of ground - grass (wet, tall, etc.), mud, rocks, sand, gravel, water, snow, ice, hillsides and the like.